Being able to detect fluid flow in a pipe has many useful applications. A key one is detecting the presence of leaks in a pipe system. Detecting flow in a system when all taps and valves are closed will usually indicate the presence of a leak in the system being monitored.
Pipe systems can be used to transmit a complete range of fluids from air and other gasses, including combustible gasses to liquids. The liquids can be water, oils or any other liquid. In any pipe system it is important to know if there is leakage in the pipe system.
Many technologies exist for measuring flow. Many involve a mechanical device in the flow e.g. an impellor or nutating disc. In order to fit these, the system must be drained and the device inserted in the pipe. This can be inconvenient. Additionally, there is a risk of leak in the area where the measurement device has been inserted.
Non-invasive measuring techniques also exist—e.g. ultrasound and thermal mass flow measurement. However, ultrasound systems tend to be relatively expensive and do not detect flow velocities less than around 1 cm/sec. Thermal mass flow metering requires the fluid to be heated by an element which requires too much power for a system to be battery powered for an extended period of time.
It is an object of embodiments of the present invention to provide a preferably non-invasive method of detecting fluid flow in a pipe system.
It is also desirable in embodiments to be able to monitor flow rates—or lack thereof remotely from a central control unit or monitoring station.
Embodiments of the present invention provide a system, device and a method for non-invasively detecting fluid flow in a pipe. Advantageously, the method and system or device may be a low powered method suitable for a battery powered monitor.
For use in understanding the present invention, the following disclosures are referred to:    US2010/206090 A1 (Stack);    EP2840362 (Kamstrup);    WO2015/097407 A1 (GRDF)    US2012/206272 A1 (Borlee);    U.S. Pat. No. 9,146,172 B2 (Trescott);    U.S. Pat. No. 7,308,824 B2 (Trescott);    http://www.aircon.panasonic.eu/GB_en/happening/4679/found to be available at 24.11.15;    http://www.neptuneoceanographics.com/thermal-leak-detection.php found to be available at 24.11.15.